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Reducing Dross in Your CNC Plasma Cuts

What is Dross and Slag?

“Dross” refers to the unwanted accumulation of waste and foreign matter resulting from molten metal created during the plasma cut. The term “dross” is often used interchangeably with the words “slag,” and “spatter.” Whichever you choose to call it, excessive buildup of hardened metal on your cut can lead to costly downtime needed for post-cut cleanup. While dross and slag are inevitable in the CNC plasma cutting process, there are several ways to reduce them.

2. High-Speed Dross and Slag

High-speed dross occurs, as its name implies, is when the cutting speed is too high. Higher speeds causes the CNC plasma arc to fall behind the torch, leaving hard globs of uncut metal on the bottom of the plate and requiring tenacious cleanup.

Boost current, being careful not to exceed 95% of your nozzles AMP rating

3. Low-Speed Dross and Slag

When your cutting speed is too slow, the plasma arc becomes like an hungry animal, looking for more metal to keep itself alive. The arc becomes wider, which in turn widens the cut to a point where the gas velocity from the torch can no longer blast the molten metal away. As a result, thick slag that would have been blown away forms on the bottom of the plate.

Solutions:

Incrementally increase cut speed until dross in minimized

Raise the torch height incrementally

Reduce current incrementally

As you can tell, having a worn/ineffective plasma consumables is one of the top causes for dross and slag appearing on your plates. Without superior equipment, you’ll find this is a recurring problem.

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